necessarily founded on slight variations of structure, and the
same species iu different stages of growth might sometimes be
referred with equal propriety to three or four genera. The
transitions, for instance, from gills to folds, from sinuses
arising from the union and ramification of gills to regular
tubes or pores; and again, when these are broken up, from
mere walls of pores, to teeth, warts, granules, etc., are almost
infinite. Undoubted Agarics, for instance, may be found
where the veins which connect the gills are so abundant and
prominent that it is scarcely possible for the tyro to believe
that he has an Agaric before him, looking merely to the
definition of the gciius. Indeed, there is an abnormal condition
of the gills of many Agarics, where an hymenium is produced
on the top of the pileus as well as beneath, iu which
the character of gills is quite lost. Such conditions have been
found in A. rubescens, A. odorus, A. cerussatus, A. campestris,
A. laccatus, and some others, and very puzzling they are to
beginners.
Amongst the naked-seeded or sporiferous Fungi, the fruit
varies but little ; but in the sporidiiferous species the modifications
of the sporidia in size, form, number of septa, etc., is
often very g rea t; insomuch that there is a disposition amongst
many fungologists to undervalue microscopic characters.
They are, however, of very great value, if the changes which
they are liable to undergo in passing from infancy to full
growth are properly borne in mind : indeed, without them it
is utterly impossible to distinguish many species. I t is not,
how-ever, within my scope to advert more particularly to this
subject here.
There is one more variation of which Fungi are capable, of
which it is necessary to add a few words. The hymenium, in
the greater part of the vast group of Hymenomycetes, is essentially
turned away from the light, and w-e have just seen in
those instances in which it is accidentally formed on the upper
surface, how much it is modified. There are, however, many
of the lower species in which it is superior, in which case the
hymenium is said to be resupinate. This character is not
however constant, for when the substance on which the
Fungus grows is placed in peculiar conditions, the edge of the
patch will become detached, and will follow the common law
of turning its hymenium away from the light, and thus from
a resupinate will have become a reflected, or even a dimidiate
Fungus. The contrary process sometimes takes place, by
which dimidiate species become resupinate, insomuch that a
vast quantity of resupinate Polypori are referable, when properly
understood, to higher species. Even some Agarics are
resupinate, hut these occasionally turn away their hymenium
from the light, or on the contrary the pileus which was at first
shortly stipitate becomes gradually excentric and turns over,
exposing the hymenium. The tendency amongst the higher
Hymenomycetes is so strong to produce the hymenium on the
lower side, that iu some cases, especially in the genus Polyporus,
if the plant be accidentally reversed, the hymenium is
gradually obliterated, aud a new hymenium formed on the
other surface. In consequence, where Polypori are in very
vigorous growth, it is often difficult to preserve them in a
natural state. A little change of situation completely obliterates
the orifices of the pores, and if an hymenium he formed
above, the whole characters of the plant are altered.
Not only do many Fungi remain long in the state of spawn
without forming fruit, but they give rise occasionally to productions
quite at variance with the characters of the perfect
plant. Hence a number of spurious genera and species originate
which are justly struck out of every scientific Flora.
The genus Rhizomorpha, for instance (as mentioned above,
p. 42), where it is really fungoid, consists, except in a solitary